(Richmond, IN)--There’s been no official explanation on the source of a loud boom that rocked Richmond Monday night.  It happened at around 10 o’clock Monday night.  Residents across the east side, in Meadow Park and in Oak Park heard it.  A resident of South 19^th said it shook her house.  It was even heard in New Paris.  There was speculation that it was a transformer, but there were no power outages.  There was also a theory that it was trains coupling.  There was no official response to the boom from police or fire last night.